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TitleMass changes and element mobility associated with the Westwood deposit ore zones, Doyon-Bousquet-LaRonde mining camp, Abitibi, Quebec
AuthorWright-Holfeld, A; Mercier-Langevin, P; Dubé, B
SourceGeological Survey of Canada, Current Research (Online) no. 2011-8, 2011, 19 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf (Adobe Acrobat Reader)
AreaDoyon; Bousquet; LaRonde; Abitibi
Lat/Long WENS-78.5000 -78.0000 48.2500 48.0000
Subjectseconomic geology; geochemistry; mineralogy; mineral deposits; mineralization; mineral occurrences; gold; alteration; hydrothermal alteration; major element geochemistry; major element analyses; trace element geochemistry; trace elements; trace element analyses; Doyon-Bousquet-LaRonde mining camp; Westwood Deposit; Abitibi Greenstone Belt; Bousquet Formation
Illustrationslocation maps; plots; tables
ProgramTargeted Geoscience Initiative (TGI-4), Gold Ore Systems
Released2011 06 07
AbstractThe world-class Westwood gold deposit in the Abitibi greenstone belt of northwestern Quebec consists of three main mineralized corridors stacked in the Bousquet Formation: the zone 2 exten-sion in the north, the north corridor in the central stratigraphy, and the Westwood-Warrenmac corridor in the south. Mass changes of major and trace elements related to the hydrothermal alteration in the upper member of the Bousquet Formation were calculated using Zr as the least mobile element. The precursors used for mass-change calculations were the least altered rocks from the neighbouring LaRonde Penna deposit, which occurs in the same stratigraphic interval as the Westwood deposit. Mass changes in the host rock of the Westwood deposit can be used to make initial inferences about fluid flow in the ore-forming hydrothermal system and define vectors toward mineralization. Extensive mass gains in K and mass losses in Na in an approximately 150 m thick zone encompassing the north corridor and Westwood-Warrenmac footwall indicate widespread effects attributed to the hydrothermal system responsible for the formation of the deposit. This, combined with Mn-rich garnet and Mg-rich chlorite previously reported, indicates that the mineralizing fluid transported substantial amounts of Mn, Mg, and K. High field-strength elements and Y show patterns of maximum mass loss associated with the Westwood-Warrenmac corridor mineraliza-tion and maximum mass gains associated with the Bousquet Fault. The hydrothermal fluids at Westwood leached the underlying rock of mobile elements and redeposited them higher in the stratigraphy.